Guest JudgeMental Posted March 8, 2014 Share Posted March 8, 2014 I am finding the ride on new 636 van very harsh indeed, wondering what pressures fellow 636 Globecar/Possl van owners run at. It is agricultural compared to my 3300 Kg Adria :-S what really helps is my LTV Roho seat cushion which was bought for long haul flights but really makes a hell of a difference..but less air would probably help as well... looking at full air suspension as well as an option...anyone looked into this at all, and I see that some just offer the rear..is this enough. the full VB system is well over 5K so out of the question edit: They are Continental tyres on 16 inch rims Link to comment Share on other sites More sharing options...
Keithl Posted March 8, 2014 Share Posted March 8, 2014 Judge, Have a look at Glide-Rite air suspension systems... Link. Everyone on an American Sprinter forum raves about them as far better than VB or any other. We've got Dunlop from Marcle but if you want true Semi-Air the Glide-Rite seems to be the way to go. Keith. Link to comment Share on other sites More sharing options...
colin Posted March 8, 2014 Share Posted March 8, 2014 Eddie, if you check the tyre safe info you will see you can reduce the pressures quite a bit, am at wrong house at moment to check the actual pressure we use , but I base it on having a possible max of 2t on each axle, still fairly firm ride thou. Link to comment Share on other sites More sharing options...
Keithl Posted March 8, 2014 Share Posted March 8, 2014 Eddie, What tyre pressures are you running? Download the Conti technical brochure Link and see what tyre pressures Conti recommend. Keith. Link to comment Share on other sites More sharing options...
Guest JudgeMental Posted March 8, 2014 Share Posted March 8, 2014 Keithl - 2014-03-08 4:03 PM Eddie, What tyre pressures are you running? Download the Conti technical brochure Link and see what tyre pressures Conti recommend. Keith. on piller it says 4.5 /5.0 bar. they are 16 inch vango tyres, M&S? not sure.....but eyesight not that great and cant read wall to be honest Link to comment Share on other sites More sharing options...
Keithl Posted March 8, 2014 Share Posted March 8, 2014 JudgeMental - 2014-03-08 5:01 PM ....but eyesight not that great and cant read wall to be honest Take a photo and enlarge it on your computer! Or on your phone if it is smart :D Keith. Link to comment Share on other sites More sharing options...
Guest Peter James Posted March 8, 2014 Share Posted March 8, 2014 Tyre presures are a compromise. For maximum fuel economy you want the tyres and suspension as hard as possible - but take that to its logical conclusion and we would have solid steel wheels with no suspension which would shake us and our vans to bits. You have you have some cushioning, even though it absorbs energy and fuel. I weighed each axle and downloaded this guide - link: http://www.tyresafe.org/images/tyre-safety-guide/motorhome-leaflet.pdf It suggests a pressure of 44psi for my maxi van, and that makes it a much better ride. Link to comment Share on other sites More sharing options...
Guest JudgeMental Posted March 8, 2014 Share Posted March 8, 2014 tried that no good. OK! thanks to Mrs M's younger eyes. continental vanco four season and in no particular order: 225/75R 121/120R 83 psi 16 C M&S edit: Peter that is equivalent to 3 bar ( van pillar says 4.5 & 5) ...... are you sure, front & back? :-S Link to comment Share on other sites More sharing options...
Robinhood Posted March 8, 2014 Share Posted March 8, 2014 83 psi (5.75 bar) is the maximum quoted pressure in the manufacturer's own data for those particular tyres, at which they are rated at an axle load of 2.9t ! Get the van weighed, and set the pressures at the point recommended in the Continental data, as posted in the link from Keith above. I'll guarantee that the pressures thus arrived at will be significantly lower, (even if you up the axle weight by 10% to allow some margin) and should, IMO, improve the ride accordingly. Link to comment Share on other sites More sharing options...
Keithl Posted March 8, 2014 Share Posted March 8, 2014 OK Eddie it is starting to make sense. If you look at pages 76-77 of the Conti brochure I linked to above you will see that your 225/75 R16C 121/120R tyres are actually 10 ply construction and hence able to be inflated to 83 psi as stated on the sidewall. You should be able to confirm this by looking at some of the small print on the tyre sidewall. As such they are likely to have a much stiffer sidewall than 'conventional' 8 ply tyres and hence be contributing to your harsh ride. So in a nutshell not much you can do about them other than weigh your axles and set pressures accordingly. HTH, Keith. Link to comment Share on other sites More sharing options...
colin Posted March 8, 2014 Share Posted March 8, 2014 Eddie, back at the old house now, and can tell you we use 60psi, but ours are not four season tyres. p.s. technicaly you could use a lower pressure, but after checking the tyre temps after a high speed trip, thats as low as I'd wish to go. Link to comment Share on other sites More sharing options...
Guest JudgeMental Posted March 8, 2014 Share Posted March 8, 2014 cheers guys..thats 4.1 bar Colin. Van about 3.100'ish unladen, so will be running at over 3400 in holiday mode i guess Link to comment Share on other sites More sharing options...
Brian Kirby Posted March 8, 2014 Share Posted March 8, 2014 Stop guessing! :-) Load it fully including passengers and take it to a weighbridge and get it weighed noting the load on each axle in turn. Then apply the pressures for load as in the Conti Tech Databook. You've got good tyres with M+S rating, so all the advantages. Good wet grip, in my experience. If you match the pressures to the actual load you should get a far more comfortable ride, even on 10PR tyres. But, you're going to Spain, where it can be hot, so running them underinflated would increase fuel consumption, possibly wear, and might cause problems. These will have a softer tread mix than summer tyres (they are not true winter tyres), so don't take chances on the pressures. They may begin to lose grip if they get hot. Link to comment Share on other sites More sharing options...
Guest Peter James Posted March 8, 2014 Share Posted March 8, 2014 JudgeMental - 2014-03-08 6:04 PM Peter that is equivalent to 3 bar ( van pillar says 4.5 & 5) ...... are you sure, front & back? :-S Van pillar is for whitevanman who just fills up the van without checking the weight. But if you weigh the axles first you can reduce it to a more suitable pressure. Chart shows 44psi for the 1600kg load on my van axles which is what I have been running at for the last 4 years - still getting 34.3mpg overall, a lovely smooth ride, and the softer tyre makes it easier to drive up kerbs. The 225/75 R16 tyres on our maxi vans is a nice deep tyre that will provide a lot of cushioning if you don't blow it up rock hard. If you were running at the maximum 3,500kg evenly distributed, - 1750kg per axle, the pressure should be 50psi. 83psi is far too much Link to comment Share on other sites More sharing options...
Brock Posted March 8, 2014 Share Posted March 8, 2014 Eddie, I sympathise with you on the ride. I've just been down the same route. Have a look at this thread: http://www.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/How-to-improve-ride-quality-/34019/ To summarise, my motorhome was lighter than when I last weighed it. For 1550kg front, Michelin said I could go down to 3.65bar. They kept to 5.5 bar on rear. I think these work out at 53psi and 80psi. I run the front at 3.9 bar [Hymer recommends 4.25 bar] and the back at 5.5bar; the ride is OK. Following a conversation with VB Air Suspension, I did consider fitting their comfort coil springs on the front until lenny helped me realised I'd already got beefed up front suspension. Link to comment Share on other sites More sharing options...
Guest JudgeMental Posted March 9, 2014 Share Posted March 9, 2014 Brock I mentioned it on your other thread but the LTV Roho air seat cushion, (about £100?) that I never thought of using in van until now! (purchased it for long haul flights) is a revelation! it really is..I can see why truckers etc...swear by them. Brian...I cant take it to a weighbridge until i get plates :-S have emailed driverite in Ireland as have had a few air assist kits from them in the past, but this drive rite also looks good! Thanks Keith, my mechanic mate looking as well regards fitting. http://www.glide-rite.com/category_s/85.htm Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 9, 2014 Share Posted March 9, 2014 I believe that the panel-van version on which your Possl is based has a 4000kg Maxi chassis that has been limited to a 3500kg maximum overall weight. I think its maximum axle-loadings will be 2100kg (front axle) and 2400kg (rear axle) which, if added together (2100kg + 2400kg = 4500kg) will be well over the 4000kg threshold and MASSIVELY over 3500kg. So the chances of you exceeding the axle-loadings would realistically be nil. Continental's inflation-pressure recommendations for your Possl's tyres and 2100kg and 2400kg axle-loadings are respectively 3.8bar/56psi and 4.6bar/67psi. Consequently, if you used those pressures until you could get the vehicle weighed as suggested above, you would be staying very much on the side of safety. It's very likely that, when weighed, you'd find that the axle-loadings were well below the 2100kg/2400kg limits and the pressures could be further reduced if you wanted to maximise comfort. Axle-loadings(kg) to inflation-pressures(bar) for your Possl's tyres are as follows 1725 - 3.0 1835 - 3.25 1950 - 3.5 2060 - 3.75 2170 - 4.0 2275 - 4.25 2385 - 4.5 2490 - 4.75 2595 - 5.0 2695 - 5.25 2800 - 5.5 2900 - 5.75 You'll note from this that (purely for illustrative purposes) if you split your Possl's 3500kg weight equally - 1750kg front and rear - you'd be looking at around 3.1bar/45psi pressures. Regarding obtaining a more comfortable ride, you'd be wasting your money fitting 'air assist' units to the rear suspension as this would stiffen up even further what must already be firm springing. You might well obtain an improvement if you had full air suspension fitted at the rear, as this replaces the metal springs, but you'd be ill advised to have this done before weighing the vehicle, adjusting the tyre pressures accordingly and seeing what that the effect was on the ride quality. I'm a mite surprised your Possl has Continental Four Season tyres and I'm guessing that they were originally specified as a factory-fitted option They would be a good choice for a motorhome in any case. There are some comments on the following blog that may be of interest http://motorhometrips.blogspot.co.uk/2013/01/winter-tyres-part-2-tyre-choices.html Link to comment Share on other sites More sharing options...
Guest JudgeMental Posted March 9, 2014 Share Posted March 9, 2014 Thanks Derek, it would be full air, air assist never a consideration as pointless. Will get down to Spain next month (depending on health) and see how I get on first....with my air seat and lower tyre pressure, there has to be an improvement, may well be enough. Will try 4/4.5 to see how I get on Link to comment Share on other sites More sharing options...
Guest Peter James Posted March 9, 2014 Share Posted March 9, 2014 Derek Uzzell - 2014-03-09 9:17 AM You'll note from this that (purely for illustrative purposes) if you split your Possl's 3500kg weight equally - 1750kg front and rear - you'd be looking at around 3.1bar/45psi pressures. Thanks for the link Derek - I was guessing the pressures based on the slightly narrower tyres quoted on the chart I had. It seems even my 44psi all round is still on the high side (for my 1600kg axle loads) No wonder Judge is finding his van a hard ride!!! Link to comment Share on other sites More sharing options...
Guest Peter James Posted March 9, 2014 Share Posted March 9, 2014 JudgeMental - 2014-03-09 9:30 AM Will try 4/4.5 to see how I get on I am sure that is too high, but you need to weigh it to get the optimum pressure. Link to comment Share on other sites More sharing options...
Guest JudgeMental Posted March 9, 2014 Share Posted March 9, 2014 Will do.... but for now have put a little more air in LTV Roho seat (was a bit squidgy yesterday) and dropped to Derek's weighs 3.8/4.5 and had a spin around the block and it feels better...not perfect but an improvement. depending on results from hospital I will know if I can get down to Spain soon.... that will be the real test, I may well get used to it....Thanks for the help :-D Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 10, 2014 Share Posted March 10, 2014 Peter James - 2014-03-09 10:42 AM Derek Uzzell - 2014-03-09 9:17 AM You'll note from this that (purely for illustrative purposes) if you split your Possl's 3500kg weight equally - 1750kg front and rear - you'd be looking at around 3.1bar/45psi pressures. Thanks for the link Derek - I was guessing the pressures based on the slightly narrower tyres quoted on the chart I had. It seems even my 44psi all round is still on the high side (for my 1600kg axle loads) No wonder Judge is finding his van a hard ride!!! As far as I can make out, the standard specification for a Possl Roadcruiser FR's tyres would be 215/75 R16C with a Load Index of 116 (= 2500kg maximum axle-load), so it's strange that this vehicle has a wider profile tyre with an even greater load-carrying capability when the 215/75 size should be plenty adequate. For experimental purposes, I'd lower the pressures down to your 44psi/3.0bar, find a rough road to drive on and see what the pressure-reduction does to the ride quality. Link to comment Share on other sites More sharing options...
colin Posted March 10, 2014 Share Posted March 10, 2014 IIRC our van has same make size and rating of tyres, but not all season. i'll have to check, but that's not likely till the weekend. p.s. 225's are an option on Maxi chassis I believe. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 11, 2014 Share Posted March 11, 2014 colin - 2014-03-10 11:41 AM IIRC our van has same make size and rating of tyres, but not all season. i'll have to check, but that's not likely till the weekend. p.s. 225's are an option on Maxi chassis I believe. According to Fiat's current Ducato handbook, the tyre options for "Maxi" (except-recreational) vehicles are 215/75 R16C 116/114R or 225/75 R16C 118/116R specifications. For 'recreational' equivalents, 225/75 R16CP 116/114Q is quoted. JudgeMental's 636 FR will have been built on a Citroen Jumper/Relay 35H base (3500kg maximum overall weight, axle maxima of 2100kg (front) and 2400kg (rear)) and not on the 40H 4000kg version I suggested earlier. Having looked at a Jumper/Relay brochure, it's evident that 35H and 40H Jumper/Relay models now have 225/75 R16C tyres as standard (as will their Ducato equivalents). The 2014 Possl and Globecar price-lists show a 215/75 R16C tyre-size as standard, but this datum must be incorrect. Link to comment Share on other sites More sharing options...
hughman Posted March 11, 2014 Share Posted March 11, 2014 My 2013 Possl came with Michelin Agilis 225/75 16 as standard. Link to comment Share on other sites More sharing options...
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